Answer: A) He has already been to the asteroid.
Explanation: In the given lines we can see Kenniston talking to another person, they are discussing whether or not they have to go back to an asteroid and that in order to do that, they need to find a ship. An inference is something that the text doesn't say in a literal way, but that we can understand when we read the text, in this case we can infer that Kenniston has already been to the asteroid because he said "we've got to get back".
